This invention relates to a phenolic resin composition for manufacturing laminates. More particularly, this invention relates to a phenolic resin composition for manufacturing laminates which comprises a modified phenolic resin admixed with polycarbonate resin so as to improve the internal plasticity of the phenolic resin and permit the production of laminates excellent in mechanical strength, especially impact strength and in punchability without incurring considerably lowering of surface hardness.
Laminates made of a phenolic resin are widely used in various fields, for example, as materials for electric instruments. However, the laminates made of a phenolic resin involve some problem in mechanical strength and mechanical workability such as punchability. Accordingly, a number of methods have been proposed hitherto with an attempt to improve these properties. For example, a method wherein a grass fabric is used as base material in place of paper, pulp or cotton linter paper is adopted chiefly for the purpose of improving mechanical strength. This method serves to improve mechanical strength but on the other hand has such a drawback that mechanical workability such as punchability of products is deteriorated and the cost of product becomes higher. There is known a method for incorporating the phenolic resin with an epoxy resin to improve the properties of the former. According to this method, the crosslinking density of the product is increased to enhance hardness and mechanical strength thereof. On the other hand, however, the impact strength and punchability of the product are deteriorated according to this method. There is also known a method wherein an alkylphenol is used as the phenol component of the phenolic resin or wherein an internally plasticized phenolic resin obtained by reacting a phenolic resin with a drying oil is used. According to this method, punchability of the product is indeed improved but its mechanical strength is hardly improved and its hardness is rather decreased. In these prior art methods, an improvement in mechanical strength of laminates is accompanied by deterioration of punchability, or alternatively an improvement in punchability of laminates is accompanied by deterioration of mechanical strength and lowering of hardness. According to these prior art methods, therefore, it is quite unable to produce laminates improved in both mechanical strength and punchability from a phenolic resin. In general, a phenolic resin has a poor compatibility with polycarbonate resin. Laminated articles obtained by using a mixture of a phenolic resin and polycarbonate resin tend to delaminate, thus resulting in serious reduction of mechanical strength. Accordingly, a mixture of a phenolic resin and polycarbonate resin fails to give practically useful laminates with satisfactory mechanical properties. Thus, there is a great demand for development of a new type modified phenolic resin which can afford laminates with improved mechanical strength, hardness and punchability.